This invention relates to the threshing, separating and cleaning of harvested grain. It relates more specifically to a harvesting apparatus.
It is envisaged that the invention will find application in the field of threshing of grain like maize (corn), wheat, beans, and the like, more particularly in the field of harvesting grain having lightweight or small, or both lightweight and small grain kernels such as wheat.
For purposes of this specification, the term xe2x80x9cthreshingxe2x80x9d (and derivatives thereof) should be interpreted as including threshing, separating and cleaning (and corresponding derivatives thereof).
Combine harvesters use rotary threshing and separation units to harvest grain like maize, wheat, beans and the like (hereinafter xe2x80x9cgrainxe2x80x9d). To thresh grain, it is required to separate the grain from the ears, pods and the like. After separating the grain from the ears, pods and the like, grain must be separated from the chaff, broken straw, debris and the like (hereinafter xe2x80x9cchaffxe2x80x9d). A fan or blower is used for this purpose whereby the fan produces an air flow stream that carries off or separates chaff from the grain. The chaff is carried off or separated from the grain because the chaff is lighter in weight than the grain. However under difficult harvesting conditions, such as in humid weather, the air flow stream may not be of sufficient velocity to move or carry the chaff. To compensate for difficult harvesting conditions and to improve performance of the rotary threshing and separation unit under these conditions, the speed of the fan or blower is increased. However when the fan or blower speed is increased, the air flow may become excessive resulting in grain kernels being discharged along with the chaff from the rotor housing which is unacceptable.
The present invention is directed to overcoming one or more of the problems set forth above.
An aspect of the invention is to improve feeding performance of a rotary threshing and separation unit having a fan or blower without an increase in grain loss.
In one aspect of this invention there are provided guiding elements arranged between the separation zone and discharge zone that do not interfere with the discharge of chaff but which precludes grain kernels from exiting the rotary threshing and separation unit.
In another aspect of the invention there are provided guiding elements that reduce the amount of grain kernel loss because of a high velocity air flow stream.
In still another aspect of the invention there are provided guiding elements and sieve means arranged in close proximity to the guiding elements and wherein the guiding elements are at an angle or inclined towards the feeding direction of the harvested crop to deflect grain kernels at high speeds back into the rotor housing so that the grain kernels deflected back can exit the rotor housing through the openings in the sieve means.
In still another aspect of the invention there are provided guiding elements that are at an angle and inclined towards the feeding direction of the harvested crop and these angles of inclinement are adjustable so that they can be adjusted to the particular working condition, such as grain type or humidity of the harvested crop.
In still another aspect of the invention there are provided helical vanes projecting over the inner surface of the rotor housing and in at least the first half of the length of the rotor housing and wherein the helical vanes are inclined towards the feeding direction of the harvested crop for improved feeding action whereby the harvested crop is accelerated faster and obtains rotational movement earlier.
In still another aspect of the invention there are provided helical vanes having an adjustable angle of inclinement so that the feeding action inside of the rotor housing can be regulated.
The above aspects are merely illustrative and should not be construed as all-inclusive.